DTC code
P0404
Exhaust Gas Recirculation Circuit Range/Performance
Technical guide
Symptoms
- Check engine light
- pinging on acceleration
- engine may run rough
- high nitrogen oxide emissions
- possible stalling
Probable causes
- Faulty EGR valve
- faulty EGR sensor
- EGR sensor wiring/connector problems
- EGR valve movement isn't smooth
- carbon buildup in EGR valve
Diagnostic steps
- Scan for other codes — verify P0404 is the only diagnostic trouble code present.
- Review freeze frame data — examine engine conditions when the code triggered.
- Inspect the EGR valve — look for carbon accumulation preventing proper valve operation.
- Seek professional help if the code persists after cleaning.
Cross-checked technical synthesis (QA). It does not replace the manufacturer's procedure.
AI here is a librarian: this page shows only what mechanics confirmed, or says “unknown”. It never suggests a diagnosis — MECCANIC interprets the code, never your car.
0 confirmed cases on P0404
Nothing confirmed yet for this code. No guess is offered on purpose.
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